Metal strip bending machine



Jan. 4, 1955 F. MALINA 2,698,642

METAL STRIP BENDING MACHINE Filed Sept. 25, 1952 2 Sheets-Sheet 1 39 Z jg j array- Jan. 4, 1955 F. MALINA' 2,698,642

METAL STRIP BENDING MACHINE Filedfiept. 23, 1952 2 Sheets-Sheet 2 kg m:

ji r726) United States Patent O METAL STRIP BENDING MACHINE Frank Malina, Chicago, 111.

Application September 23, 1952, Serial No. 311,015

9 Claims. (Cl. 153-54) Various machines devised for bending flat metal strips edgewise into individual rings or into spirals which may later be cut up into rings are now in use. Usually these divided rings are simply partial rings of larger diameter than the diameters which they must have in their final positions of use in cylinders and elsewhere. In such cases, after the rings are contracted to close the gaps therein, they are no longer round and do not, for example, accurately fit a cylinder for which they are intended. Also, the rings usually are not flat, the metal being distorted, during bending, especially in a manner to give them a slight frustoconical shape.

The main object of the present invention is to provide a simple and novel machine to produce rings that are perfectly fiat and are perfectly round when contracted to close the gaps therein.

A further object is to provide a machine that is capable of handling strip materials of different widths and thicknesses, and of forming rings of many different diameters, without requiring any alterations except those which a user himself can make easily and quickly.

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the claims, but, for a full understanding of the invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawings, wherein:

Figure 1 is a front elevational view of a machine embodying my invention, showing a strip in the process of being inserted.

Fig. 2 is a view similar to Fig. 1, on a larger scale, showing only the upper part of the machine, with the forming roller in a different position and the strip having moved ahead.

Fig. 3 is a section on line 3-3 of Fig. 2.

Fig. 4 is a view, looking at the swinging member, which supports the forming roller, from a point to the right of Fig. 3.

Fig. 5 is a section on the irregular line 55 of Fig. 2.

Fig. 6 is a front view of the forming roller separated from all parts of the machine except the supporting shaft therefor.

Fig. 7 is a section on line 77 of Fig. 6.

Fig. 8 is a view on a larger scale, similar to Fig. 1, showing the blade in the act of making a mark on the strip.

Fig. 9 is a section on line 9-9 of Fig. 8.

Fig. 10 is a view looking at the face of one and a fraction turns of a spiral fashioned by the machine.

Fig. 11 is a face view of a closed ring formed from somewhat less than a complete turn in Fig. 10.

In the drawings I have shown a simple machine embodying my invention and, for the sake of brevity, the details of only this particular form will be described.

Referring to the drawings, 1 is a sturdy, vertical plate providedwith a leg 2, on the lower end of which is a foot 3, adapted to be fastened to a suitable stationary support by bolts 4 or other suitable means. A heavy horizontal shaft 5 extends through the center of plate 1 from the rear. This shaft terminates in an extension 6, of greatly reduced diameter, from a point that lies a little in front of the plate. On shaft 5, just in front of the plate, is a washer 7 and, in front of the washer, on extension 6, is an anvil roller comprising two thick discs, 8 and 9, of the same diameter, together with an intervening washer 10 of smaller diameter. On shaft 2,698,642 Patented Jan. 4, 1955 6, outwardly from the anvil roller, is a large, thick washer 11 engaged by a small washer 12 which, in turn, 1s engaged by a nut 14 on the free end of such shaft element.

Surrounding shaft 5, just behind plate 1, is a hub 15 on and remote from the ends of a long, sturdy bar 16; the bar, thus comprising two arms 17 and 18 extending in opposite directions from the hub, being adapted to oscillate about the axis of the shaft. Connected to the lower end of the lower arm 17 of the bar is a rod or strut 19 that extends slidably through a lower stationary post 20. Member 19 may be locked to post 20 by a set screw 21 or otherwise. Member 19 may be provided with graduations 22 to permit bar 16 to be adjusted ac curately, into any desired angular position, by shifting the rod or strut lengthwise until the proper mark thereon registers with a side face of post 20.

The upper arm 18 of bar 16 serves to support a forming roller 24 which cooperates with the anvil roller. Arm 18 contains a slot 25 that extends through the same from front to rear and from a point near the upper end of the arm to a point near the hub 15. Extending through this slot is a sturdy horizontal shaft 26. The diameter of the shaft equals the width of the slot. On this shaft, in front of the arm, is a sturdy collar 27. On the rear end of the shaft are a washer 28 and a nut 29; the nut forcing the washer against the arm and drawing the shaft rearwardly until the arm is clamped between the collar and the washer. On one side of arm 18 is a vertical row of graduations 30 with which cooperates a mark 31 on collar 27. By means of these graduations, and the cooperating mark, the shaft and the forming roller may be set accurately at any desired distance from the anvil roller.

Shaft 26 may be moved up and down by means of a long screw 32 extending through the top of arm 18, down into slot 25 and through the shaft; the screw having on its upper end a wheel 34 by which it may be turned. The screw is prevented from moving lengthwise by a pin 35 that extends, crosswise of the shaft, through the arm at ahppint permitting it to enter a groove 36 encircling the s a t.

Forming roller 24 is primarily a thick disc disposed in the plane of the groove 37 surrounding the washer 10 in the anvil roller. As this disc or roller revolves, the gap between the same and the anvil roller must increase from a minimum to a maximum and back to the minimummum, once during each revolution.

In the arrangement shown, the disc member of the forming roller is perfectly round and is mounted on a hub 38 in such a manner as to be slightly eccentric with respect to the supporting shaft. In order that the degree of eccentricity may be varied, the hub is a separate piece that extends through a hole 39 in the disc; this hole being slightly elongated. The hub has a flange 40 that engages with the rear side of the disc and is fastened to the latter by screws 41. These screws extend through holes 42 in the disc; these holes being elongated to the same extent and in the same direction as is the central hole 39. A nut 43 on the front end of shaft 26 prevents the forming roller from coming off. On the front side of roller 24 is a central, annular rib 44, the internal diameter of which is a little larger than the diameter of the hub. Two screws 45 extend through this rib on opposite sides of and aligned with the long axis of hole 39. These screws engage the hub and determine the degree of eccentricity of the roller. The elongated holes 42 allow the disc member of this roller to be shifted, relative to the hub, when screws 41 are loosened; the latter screws being again tightened after the adjustment has been made.

A small, idle guide roller 46 is mounted on plate 1, for rotation about an axis parallel to the axes of the other two rollers; this roller being so positioned that the gap between the periphery thereof and the bottom of the groove 37 is at least as great as the width of the strip material to be operated upon. In the arrangement shown, roller 46 is rotatable on a headed pintle 47 that extends through plate 1 and into a thick washer 48 in which it is a tight fit. The washer is held to plate 1 by screws 49.

Secured at one end to the front side of the disc member of the forming roller 24 is a long spring blade 50 the free end 51 of which is bent back in overlapping relation to the edge face of the disc. This free end or tip is tapered to a point that is sufficiently hard to scratch a lme onto the strip material when drawn across the same while under a little pressure.

This blade is so located that it engages a strip, passing through the machine, in the vicinity of the portion that has been subjected to the greatest bending stress. In the particular example illustrated, the tip of the blade is displaced about 45 from the point on the forming roller that comes closest to the anvil roller.

Power for operating the machine is delivered to the anvil roller through shaft 5, and the other two rollers are caused to rotate solely through driving forces delivered thereto by a strip passing through the machine.

When strip material of given width and thickness is to be operated upon, there is inserted in the anvil roller a washer the thickness of which is about one thousandth inch less than the thickness of the strip material and the diameter of which is such that the groove in the anvil roller has a depth equal to at least two thirds or more of the width of such strip.

A forming roller disc having the same diameter as the external diameter of the ring to be produced is selected, and is mounted on hub 38 in such a manner as to provide the desired eccentricity. The forming roller is then adjusted radially of the anvil roller so that the minimum gap between them (measured from the bottom of groove 37) is at least equal to the width of the strip material, and may be somewhat greater.

The particular machine illustrated is one in which shaft is designed to be secured in a lathe-driven chuck and, therefore, a lathe (not shown) is made to serve as the support for leg 2 and post 20, while the shaft is engaged in the chuck.

Before a strip is inserted in the machine, arm 16 is shifted in the direction to bring the forming roller 24 to or near guide roller 46, as in Fig. 1. An end of a strip S is then inserted from below, between the idle and anvil rollers, in the plane of groove 37, and the anvil roller is slowly turned in the counterclockwise direction. Since these two rollers are sufficiently close to each other, the strip is drawn ahead and forced into the groove in the anvil roller. As soon as the strip has become well started through the machine, the forming roller is swung toward the left, as viewed in Fig. 1, to the position shown by graduations 22 to be the proper one for the kind of product desired. It will be noted that the gap between the anvil roller and the forming roller does not change on account of a bodily swinging movement of the forming roller.

The two disc members of the anvil roller are sufficiently elastic to spring a little in order to widen the groove between them for the reception of the strip. Once partially entered in the groove, the strip is held in such a tight grip that it is pulled steadily into the machine until the end of the strip is reached.

As the strip passes through the machine. it is bent into a series of helices each of greater circumferential length than the corresponding dimension of the circular ring which is to be the end product. The reason for this is that each helical turn is not a circle when flattened, but is slightly oval. However, a section of the bent material, of the same circumferential length as that of a closed ring of the desired diameter, forms a ring that is round when the ends of such section are brou ht together. Therefore, when one of my rings is placed on a piston operating in a cvlinder, it forms a true circle of the same diameter as the cylinder.

In actual practice the rings are not made one at a time from short pieces, but from long strips which are afterwards divided into individual rings. The division of a series of coils into individual rings, accurately, quickly and without waste of material, is made possible through the use of the marking blade. During the operation of the machine, the point of greatest bending stress in the strip is about midway between the guide roller and the tip of the marking blade. with the parts in the positions which they occupy in Fig. 8. This stress is of course the greatest at the time when the gap between the anvil roller and the forming rol er is smallest. Bv placing the blade as heretofore described, namely trailing the spot on the forming roller which makes the closest to the anvil roller, it marks the stri at each point of greatest stressing whenever the strip has moved ahead approximately far enough to bring such point near the plane contaming the axes of the anvil and forming roller.

With the forming roller as viewed in the drawings turning in the clockwise direction, the bent end or tip 51 of the blade 50 first engages the upper edge of the strip at the point which, shortly before, was subjected to the maximum bending stress. One tapered side of the tip acts as a cam and, shortly before the conditions illustrated in Figs. 8 and 9 are in effect, forces the tip to move toward the observer and then onto the front face of the strip. By the time the tip reaches the position illustrated in these latter figures, the point of the blade has travelled radially a little distance toward the axis of the anvil roller. As the rollers continue to turn, these movements of the tip of the blade are reversed and it drops off the edge of the strip at the point of entry, and the blade springs back into its idle, unstressed position.

The movements of the point of the blade across the face of the strip result in leaving a short radial scratched line M on the strip. These marks appear on the coils S into which the strip, as shown in Fig. 10, is transformed.

Upon severing the coiled strip at the marks M, I obtain open, non circular rings the strip length of which is equal to that of the circular ring which is the final form to be attained. Thus, in Fig. 11, is shown one of these severed coils contracted to close the gap and form a complete circular ring S The reason for the true curvature of the contracted ring is that the two meeting ends have been bent a little more sharply than the remainder of the ring, and so conform to the desired curvature without being stressed as is the remainder of the ring when the ring is contracted.

It makes no difference where the marking blade stands at the time of starting a coiling operation, for the first mark will always be made at a proper point on the strip. There may be a little waste of material through discarding a short piece at the starting end of a strip, after severing the coiled material at the first mark, but there is no further waste of material except, perhaps, a short piece at the other end of the strip. The waste at each end will always be less than the amount of strip material needed for one of the rings.

By making the groove in the anvil roller narrower than the thickness of the strip material, and of a depth to allow less than one third of the width of a strip to protrude therefrom, I not only am able to drive the forming roller through its contact with the strip, but also prevent dishing or other undesirable deformations in the strip material during manufacture of the rings.

By reason of the various adjustments provided and interchangeable washers for the anvil roller and disc elements of different sizes for use as form rollers, I am able to operate my machine on strip material of various widths and thicknesses and to produce rings of various diameters.

I claim:

1. In a machine for bending flat metal strip material edgewise to form a structure in the nature of a spiral formed of successive, like sections each less than a complete turn and constituting, when separated from each other, rings that contain gaps and are of such contour that they become round when compressed to close the gaps: an anvil roller containing a circumferential groove, a support on which the aforesaid roller is mounted, means to drive the aforesaid roller, a guide on the support in position to force into said groove a metal strip fed on edge between the guide and the said anvil roller; and means adjacent to the anvil roller and sufiiciently remote from the guide to compel the strip to bend over that roller; said means including a round forming roller rotatable about an axis parallel to the axis of the anvil roller and displaced a slight distance from its own axis; and said forming roller being separated from the anvil roller, at the point of nearest approach to each other, by a gap the maximum width of which is less than the width of said strip material.

2. A machine as set forth in claim 1, wherein the groove in the anvil roller has a width slightly less than the thickness of the strip material to be received therein.

3. A machine as set forth in claim 1, wherein there is a member mounted on the support so as to be adjustable angularly about the axis of the anvil roller, the forming member is mounted on said member, and means are present to lock said member in any position into which it may be placed.

4. In a machine for bending flat metal strip material edgewise to form a structure in the nature of a spiral formed of successive, like sections each less than a complete turn and constituting, when separated from each other, rings containing gaps and of such contour that they become round when compressed to close the gaps: an anvil roller containing a circumferential groove, a support on which the anvil roller is mounted, means to drive the anvil roller, a guide roller, freely rotatable on the support in the plane of and separated from the anvil roller a distance not over one half the width of the strip material to be worked, that forces into the said groove such strip material when the latter is fed on edge between the two aforesaid rollers; means adjacent to the anvil roller and sufficiently remote from the guide roller to compel the strip to bend over the anvil roller; said means including a round forming roller freely rotatable about an axis parallel to the axis of the anvil roller and displaced a slight distance from its own axis, the forming roller being separated from the anvil roller, at the point of nearest approach to each other, by a gap the maximum width of which is less than the width of the strip material, and the circumference of the forming roller being equal to the length desired in the said sections of the spiral.

5. A machine for bending flat metal strip material edgewise to form a structure in the nature of a spiral formed of successive, like sections each less than a complete turn and constituting, when separated from each other, rings containing gaps and being of such contour as to become round when compressed to close the gaps, comprising: a support, an anvil roller mounted on said support and containing a circumferential groove, means to drive the anvil roller, a guide roller on the support in position to force into said groove a metal strip fed on edge between the guide roller and the anvil roller; means adjacent to the anvil roller and sutficiently remote from the guide roller to compel the strip to bend over the anvil roller; said means including a round forming roller freely rotatable about an axis parallel to the axis of the anvil roller and displaced a slight distance from its own axis, and separated from the anvil roller by a gap the maximum width of which is less than the width of the strip material; and the circumference of the forming roller being equal to the desired length of the aforesaid bent strip sections.

6. A machine as set forth in claim 5, having, in ad dition, a device carried by the forming roller for making on a strip passing through the machine a mark at each point where the strip has the sharpest bend due to the nearness of the forming roller to the anvil roller.

7. A machine as set forth in claim 5, wherein the point of sharpest bend in a strip is made before such point reaches the plane containing the axes of rotation of the anvil roller and the forming roller, and wherein the forming roller has thereon a device that is displaced from said plane, in the same direction and at the same distance, as each such point at the time such a sharp bend is being made; which device has thereon an element to engage the strip and mark it whenever such element and a point of sharpest bend simultaneously reach said plane.

8. A machine as set forth in claim 5, wherein the immediate support for the forming roller is a stub shaft, and wherein that roller is provided with a hub rotatable on the shaft and with means to shift the hub and roller slightly angularly of the shaft.

9. A machine as set forth in claim 5, wherein the groove in the anvil roller has a depth at least two thirds as great as the width of the strip material operated upon.

References Cited in the file of this patent UNITED STATES PATENTS 200,196 Helm Feb. 12, 1878 801,737 Monnier Oct. 10, 1905 1,915,312 Hauf June 27, 1933 2,450,041 Groves Sept. 28, 1948 

